In the prior art, it is a common practice to blend silicone oil in cosmetics to enhance water repellency for the purpose of sustaining a skin protection effect. In water-in-oil (W/O) emulsion compositions, silicone oil is used as oil ingredient to form light feeling, less sticky and water repellent compositions. Regarding the preparation of such W/O emulsions containing silicone oil, Patent Document 1 discloses the use of an emulsifier such as polyoxyalkylene-modified organopolysiloxane and Patent Document 2 discloses the use of silicone branched polyether-modified silicone which is further increased in compatibility with silicone. However, these straight chain silicone activators alone are difficult to prepare high water content emulsions. When they are blended in high proportions for stabilization, a fresh feel on use is rarely obtainable.
In the field of makeup and sunscreen cosmetics, it is desired from the standpoint of daily use to develop long lasting cosmetics. Outstanding problems for these cosmetics include deterioration of makeup by sweat and sebum secreted from the skin and color transfer due to secondary sticking to cups or the like. One solution is to utilize organosilicon resins because they have water resistance, sebum resistance, water repellency and film-forming ability.
The organosilicon resins have essentially silicon-containing three-dimensional structures comprising Q units (SiO4/2) and T units (RSiO3/2). Owing to many advantages including weather resistance, heat resistance, water repellency, and electric insulation, they are used as intermediate materials destined for pressure-sensitive adhesives, rubber compounds, parting agents, and coating agents. Since the recent discovery of some organosilicon resins having a film-forming ability, the demand for these resins as cosmetic raw materials for foundation, lipstick, eyeshadow, cream, milky lotion and hair-care cosmetics is increasing. For example, a solution of organosilicon resin in cyclic silicone is blended in cosmetics as disclosed in Patent Document 3. However, trimethylsiloxysilicic acid lacks an emulsifying ability.